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The echinoderm Loxechinus albus has a symbiotic relationship with the pinnotherid crustacean Pinnaxodes chilensis. Females of the crustacean develop in the terminal section of the sea urchin's digestive system, remaining there for life. This relationship has been suggested as commensalism. However, a potential negative impact on gonadal development and on the morphology of the sea urchin's digestive system suggest that it is instead parasitic. To study if there is a negative impact of the crustacean symbiont on the host, specimens of L. albus of all sizes were collected from a rocky shore in southern Chile. The gonadal and somatic tissues of sea urchins that were and were not harboring the pinnotherid were weighed and compared. Our results show that the presence of the pinnotherid was related to sea urchin gonads of lower biomass, decreased gonadosomatic index levels, and alterations in the morphology of the terminal portion of the host digestive system. The lower gonadal biomass suggests a negative impact on gamete production as well as a diversion of energy due to changes of the digestive system tissues and the potential consumption of algal food by the resident crustacean. These results suggest that the prolonged relationship between these two species is one of parasitism rather than one of commensalism.

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Understanding what determines spatio-temporal changes in echinoderm assemblages from an integrative perspective that considers biodiversity, species evenness, and species' niches could permit superior community-scale characterizations of habitat resilience to disturbance. Such an approach was taken herein by tracking a Central Mexican Pacific echinoderm assemblage between 2012 and 2021, and higher richness, diversity, evenness, and functional entity counts were associated with more heterogeneous benthic assemblages. Echinoderm taxonomic composition was influenced by ENSO events, with higher functional diversity found during La Niña events. Conservation strategies should focus on species with unique functional traits to maintain the balance of coral community functionality.

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Sea urchins play a key role in the marine environment, contributing to maintain a balance in benthic ecosystems. Toxopneustes roseus acts as a regulator of rhodolith beds and is a key species as a bioturbation promoter, while Rhyncholampas pacificus moderates the detritus content of sediment through various mechanisms and contributes to accelerating the circulation of organic matter. However, nothing is known about their early development, so the objective of this research is to characterize the embryonic and larval development of specimens of the two species from the southern Mexican Pacific and identify the causes that produce their differences. The embryonic development of T. roseus lasted approximately 20 â€‹h; the echinopluteus larva appeared at 23 â€‹h and culminated in around 12 days with an eight-armed larva. Metamorphosis was reached at 18 days. The embryonic development of R. pacificus lasted about 15 â€‹h; the larva emerged at 20 â€‹h and culminated in about two days with an eight-armed larva. The metamorphosis was completed in 9 days. The reproductive output of both species determines their development time and the structure of their larvae; therefore, the energy of R. pacificus is invested in reaching metamorphosis earlier to ensure that its larvae, which are not very abundant, settle and recruit to the population. Regarding T. roseus, the longest permanence in the plankton is efficiently maintained by its numerous larvae through the presence of mobile arms and the shift of the swimming function to the epauletes. This is the first work that characterizes the early development of a species of the genus Toxopneustes and of the only living species of the genus Ryncholampas. The information generated in this work is essential to gaining knowledge about these groups of echinoids, especially the effect of the environment on their early development.

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Introduction: Sea urchins in the order Spatangoida are the most diverse group of extant echinoids. Objective: Describe a new genus and species of Spatangoida from abyssal depths, and add new records for known species. Methods: Specimens were collected during several cruises at different areas of the southwestern Atlantic Ocean (SWAO), among 37-55° S latitude at depths ranging from 55 to 3 000 m. We present morphological and ultrastructure analyses. Results: Corparva lyrida gen. et sp. nov. (Palaeotropidae) is described from the Mar del Plata Canyon on the Argentine continental slope (2 950 m depth), the first record of this family from Argentina. Corparva gen. nov. differs in having an apical system semi-ethmolytic, and labrum reaching to rear part of second adjacent ambulacral plate. We also report the northernmost distribution and deepest record for Brisaster moseleyi (38° S latitude, 2 212 m depth), the northward extension of the distribution range of Tripylus excavatus (39° S latitude, 74 m depth), and the first record of Abatus philippii and Abatus agassizii at the Burdwood Bank/MPA Namuncurá. Conclusions: The present work brings novel and updated data about the diversity and distribution of spatangoids from the SWAO, including the description of C. lyrida gen. et sp. nov., and new records of species. This shows how much remains to be known about the diversity and distribution of heart urchins in the SWAO, especially from the deep-sea.

Introducción: Los erizos de mar del orden Spatangoida son el grupo más diverso de equinoideos recientes. Objetivo: Describir un nuevo género y una nueva especie de Spatangoida de profundidades abisales, y reportar nuevos registros para especies conocidas. Métodos: Los ejemplares fueron recolectados durante varias expediciones a diferentes áreas del Océano Atlántico sudoccidental (OAS), entre las latitudes 37-55° S y abarcando profundidades desde 55 a 3 000 metros. Presentamos análisis morfológicos y de ultraestructura. Resultados: Corparva lyrida gen. et sp. nov. (Palaeotropidae) fue descripta para el cañón submarino Mar del Plata en el talud continental de Argentina (2 950 m de profundidad), el primer registro de esta familia para Argentina. Corparva gen. nov. difiere en tener un sistema apical semi-etmolítico y labrum que llega a la parte posterior de la segunda placa ambulacral adyacente. También informamos la distribución más septentrional y el registro más profundo para Brisaster moseleyi (latitud 38° S, 2 212 m de profundidad), la extensión hacia el norte del rango de distribución de Tripylus excavatus (latitud 39° S, 74 m de profundidad) y el primer registro de Abatus philippii y Abatus agassizii en el Banco Burdwood/AMP Namuncurá. Conclusiones: El presente trabajo aporta datos novedosos y actualizados sobre la diversidad y distribución de erizos de mar espatangoideos del OAS, incluyendo la descripción de C. lyrida gen. et sp. nov., y nuevos registros para especies conocidas. Esto muestra cuánto queda por conocer sobre la diversidad y distribución de los erizos corazón en el OAS, especialmente de las profundidades marinas.

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Introducción: La acuicultura de equinodermos en América Latina es incipiente, pero representa una nueva frontera para la producción de alimentos marinos altamente nutritivos, con especies nativas de alto valor comercial que ofrecen un gran potencial en comparación con las debilitadas pesquerías bentónicas artesanales. Metodología: Se revisó la literatura sobre pepinos de mar, erizos de mar y estrellas de mar hasta el año 2020. Resultados: Para el 2020, había 17 especies nativas con importantes avances en reproducción, larvicultura, crecimiento, tratamiento e identificación de enfermedades y nutrición en México, Belice, Panamá, Colombia, Ecuador, Perú, Brasil, Chile y Argentina. Conclusiones: La acuicultura de equinodermos en América Latina está avanzando y se beneficiaría de los sistemas multitróficos para expandirse y diversificarse, reduciendo la presión sobre las pesquerías agotadas.

Introduction: Echinoderm aquaculture in Latin America is incipient, but it represents a new frontier for the highly nutritious marine food production, with native species of high commercial value offering a vast potential when compared to the weakened artisanal benthic fisheries. Methodology: We reviewed the literature on sea cucumbers, sea urchins, and starfish up to the year 2020. Results: By 2020, there were 17 native species with important advances in reproduction, larviculture, growth, treatment and identification of diseases, and nutrition, in Mexico, Belize, Panamá, Colombia, Ecuador, Peru, Brazil, Chile and Argentina. Conclusions: Echinoderm aquaculture in Latin America is advancing and would benefit from multitrophic systems to expand and diversify, reducing the pressure on depleted fisheries.

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Antioxidant molecules cause a decrease in oxidation, inhibiting the formation of free radicals. Known as reactive oxygen species (ROS), free radicals are molecules with one or more unpaired, unstable, highly reactive electrons capable of oxidizing neighboring molecules to gain electrons, damaging adjacent cells. Oxidative processes and ROS formation occur physiologically and, also in several pathologies, therefore, antioxidants are extremely relevant for disease prevention. Some chronic and neurodegenerative diseases have already been reversed in animal studies with the use of antioxidants such as cancer, cardiovascular disease (including atherosclerosis), autoimmune diseases, diabetes, Parkinson's disease, inflammation (including arthritis), and aging. Pigments found in sea urchins have already been associated with antioxidant activity. Therefore, the objective of this work is to search for new molecules with antioxidant activity in four species of sea urchin. The spines, carapace and coelomic fluid of the tropical species Echinornetra lucunter, Lytechinus variegatus, Arbacia lixula and the species Antarctica Sterechinus neumayeri were used in the study. Individually, the materials were fractionated into solid phase extraction (in C18 cartridges) eluting with 25, 50, 75 and 100°/o methanol v I v. The fractions submitted to RP-HPLC, in column C18 aiming at obtaining more pure molecules. The peaks obtained by chromatography were tested in in vitro antioxidant activity assays and tested too in MALDl-ToF. The species Echinometra lucunter and the Antarctica Sterechinus neumayeri presented promising results, which are demonstrated in this work.

Moléculas antioxidantes causam diminuição da oxidação, inibindo a formação de radicais livres. Conhecidos como espécies reativas de oxigênio (ROS), os radicais livres são moléculas com um ou mais elétrons não pareados, instáveis e altamente reativos, capazes de oxidar moléculas vizinhas para ganhar elétrons, danificando células adjacentes. Processos oxidativos e formação de ROS ocorrem fisiologicamente e, também em diversas patologias, portanto, os antioxidantes são extremamente relevantes para a prevenção de doenças. Algumas doenças crônicas e neurodegenerativas já foram revertidas, em estudos em animais, com o uso de antioxidantes, como câncer, doenças cardiovasculares (incluindo aterosclerose), autoimunes, diabetes, doença de Parkinson, inflamações (incluindo artrite) e envelhecimento. Pigmentos encontrados em ouriços-do-mar já foram associados à atividade antioxidante. Sendo assim, o objetivo deste trabalho é buscar novas moléculas com atividade antioxidante em quatro espécies de ouriço-do-mar. Os espinhos, carapaças e líquido celomático das espécies tropicais Echinometra lucunter, Lytechinus variegatus, Arbacia lixula e da espécie Antártica Sterechinus neumayeri foram utilizadas no estudo. Individualmente, os materiais foram fracionados em extração em fase sólida (em cartuchos C18) com eluição por 25, 50, 75 e 100% de metanol v/v. As frações submetidas a RP-HPLC, em coluna C18 visando obtenção de moléculas mais puras. Os picos obtidos pela cromatografia foram testados em ensaios in vitro de atividade antioxidante e também pelo MALDlToF. As espécies Echinometra /ucunter e a antártica Sterechinus neumayeri, apresentaram resultados promissores, os quais são demonstrados nesse trabalho.

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Antioxidant molecules cause a decrease in oxidation, inhibiting the formation of free radicals. Known as reactive oxygen species (ROS), free radicals are molecules with one or more unpaired, unstable, highly reactive electrons capable of oxidizing neighboring molecules to gain electrons, damaging adjacent cells. Oxidative processes and ROS formation occur physiologically and, also in several pathologies, therefore, antioxidants are extremely relevant for disease prevention. Some chronic and neurodegenerative diseases have already been reversed in animal studies with the use of antioxidants such as cancer, cardiovascular disease (including atherosclerosis), autoimmune diseases, diabetes, Parkinson's disease, inflammation (including arthritis), and aging. Pigments found in sea urchins have already been associated with antioxidant activity. Therefore, the objective of this work is to search for new molecules with antioxidant activity in four species of sea urchin. The spines, carapace and coelomic fluid of the tropical species Echinornetra lucunter, Lytechinus variegatus, Arbacia lixula and the species Antarctica Sterechinus neumayeri were used in the study. Individually, the materials were fractionated into solid phase extraction (in C18 cartridges) eluting with 25, 50, 75 and 100°/o methanol v I v. The fractions submitted to RP-HPLC, in column C18 aiming at obtaining more pure molecules. The peaks obtained by chromatography were tested in in vitro antioxidant activity assays and tested too in MALDl-ToF. The species Echinometra lucunter and the Antarctica Sterechinus neumayeri presented promising results, which are demonstrated in this work.

Moléculas antioxidantes causam diminuição da oxidação, inibindo a formação de radicais livres. Conhecidos como espécies reativas de oxigênio (ROS), os radicais livres são moléculas com um ou mais elétrons não pareados, instáveis e altamente reativos, capazes de oxidar moléculas vizinhas para ganhar elétrons, danificando células adjacentes. Processos oxidativos e formação de ROS ocorrem fisiologicamente e, também em diversas patologias, portanto, os antioxidantes são extremamente relevantes para a prevenção de doenças. Algumas doenças crônicas e neurodegenerativas já foram revertidas, em estudos em animais, com o uso de antioxidantes, como câncer, doenças cardiovasculares (incluindo aterosclerose), autoimunes, diabetes, doença de Parkinson, inflamações (incluindo artrite) e envelhecimento. Pigmentos encontrados em ouriços-do-mar já foram associados à atividade antioxidante. Sendo assim, o objetivo deste trabalho é buscar novas moléculas com atividade antioxidante em quatro espécies de ouriço-do-mar. Os espinhos, carapaças e líquido celomático das espécies tropicais Echinometra lucunter, Lytechinus variegatus, Arbacia lixula e da espécie Antártica Sterechinus neumayeri foram utilizadas no estudo. Individualmente, os materiais foram fracionados em extração em fase sólida (em cartuchos C18) com eluição por 25, 50, 75 e 100% de metanol v/v. As frações submetidas a RP-HPLC, em coluna C18 visando obtenção de moléculas mais puras. Os picos obtidos pela cromatografia foram testados em ensaios in vitro de atividade antioxidante e também pelo MALDlToF. As espécies Echinometra /ucunter e a antártica Sterechinus neumayeri, apresentaram resultados promissores, os quais são demonstrados nesse trabalho.

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Size, growth, and density have been studied for North American Pacific coast sea urchins Strongylocentrotus purpuratus, S. droebachiensis, S. polyacanthus, Mesocentrotus (Strongylocentrotus) franciscanus, Lytechinus pictus, Centrostephanus coronatus, and Arbacia stellata by various workers at diverse sites and for varying lengths of time from 1956 to present. Numerous peer-reviewed publications have used some of these data but some data have appeared only in graduate theses or the gray literature. There also are data that have never appeared outside original data sheets. Motivation for studies has included fisheries management and environmental monitoring of sewer and power plant outfalls as well as changes associated with disease epidemics. Studies also have focused on kelp restoration, community effects of sea otters, basic sea urchin biology, and monitoring. The data sets presented here are a historical record of size, density, and growth for a common group of marine invertebrates in intertidal and nearshore environments that can be used to test hypotheses concerning future changes associated with fisheries practices, shifts of predator distributions, climate and ecosystem changes, and ocean acidification along the Pacific Coast of North America and islands of the north Pacific. No copyright restrictions apply. Please credit this paper when using the data.

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ResumenLas especies Echinometra lucunter, Echinometra viridis, Lytechinus variegatus, Tripneustes ventricosus, and Diadema antillarum son los erizos de mar más comunes en los hábitat litorales del Caribe. Los erizos de mar T. ventricosus y L. variegatus habitan generalmente los pastos marinos mientras que las otras tres especies se encuentran asociadas a sustratos rocosos. Los hábitos alimentarios de estas especies han sido bien documentados y son reconocidas como herbívoros - omnívoros; sin embargo, pocas de estas especies han sido caracterizadas isotópicamente. Utilizamos los isótopos estables para caracterizar estas cinco especies de erizos y establecer las posiciones tróficas para las especies que cohabitan los mismos ecosistemas. También cuantificamos la contribución de los recursos alimentarios para E. lucunter. Los erizos T. ventricosus y D. antillarum mostraron los mayores valores de δ15N y valores similares de δ13C que variaron desde -11.6 ± 0.63 a -10.4 ± 0.99 %; donde el erizo E. lucunter mostró los valores más negativos con -15.40 ± 0.76 %. Las comunidades de algas no mostraron diferencias en valores promedio de δ15N (F= 1.300, df= 3, p= 0.301), pero sí mostraron variaciones en los valores de δ13C (F= 7.410, df= 3, p= 0.001). Los estudios de amplitud de elipses de nicho determinaron que las especies de los biotopos rocosos (D. antillarum, E. lucunter y E. viridis) no mostraron solapamiento de nicho. Similar resultado también se encontró en las especies de erizos que habitan en los pastos marinos. Sin embargo, la distancia entre estas dos especies fue menor respecto a la distancia entre las especies de erizos que habitan en los sustratos rocosos. Nuestros resultados muestran que las especies que habitan en los pastos marinos mostraron valores más elevados de δ13C en comparación con las especies de los sustratos rocosos. No se encontraron diferencias espaciales para E. lucunter en δ15N, pero sí en δ13C. Los modelos de mezcla bayesianos demuestran la plasticidad alimentaria de E. lucunter, especie capaz de utilizar múltiples recursos algales dependiendo de la disponibilidad por sitio. Semejanzas en δ15N entre D. antillarum y T. ventricosus parecen indicar similitudes tróficas entre ambas especies. Si bien T. ventricosus es reconocido como omnívoro, D. antillarum siempre ha sido considerado un herbívoro generalista. Finalmente, la falta de solapamiento entre las especies en los dos biotopos parece indicar una estrategia de partición de recursos para evitar la competencia de nicho entre especies concurrentes.

AbstractThe species Echinometra lucunter, Echinometra viridis, Lytechinus variegatus, Tripneustes ventricosus, and Diadema antillarum are the most common sea urchins of littoral habitats in the Caribbean. T. ventricosus and L. variegatus are associated with seagrass beds, while the other three species usually inhabit hardground substrates. Food preferences of these species are well documented and they are commonly accepted as being primarily herbivorous-omnivorous; nevertheless, few of them have previously been characterized isotopically. We used this approach for assessing the isotopic characterization of five echinoids. We established the trophic position of two groups of co-occurring species and quantified the contribution of food resources in the diet of Echinometra lucunter, considered the most common sea urchin in the Caribbean region. The species T. ventricosus and D. antillarum showed the highest values of δ15N. Sea urchins exhibited similar values of δ13C varying from -11.6 ± 0.63 to -10.4 ± 0.99%. The echinoid E. lucunter displayed the lowest values of carbon, from -15.40 ± 0.76%. Significant differences among species were found for δ15N and δ13C. Seaweed communities exhibited no differences among sites for overall δ15N (F= 1.300, df= 3, p= 0.301), but we found spatial differences for δ13C (F= 7.410, df= 3, p= 0.001). The ellipse-based metrics of niche width analysis found that the hardground biotope species (D. antillarum, E. lucunter, and E. viridis) did not overlap each other. Similar results were obtained for the co-occurring species of the seagrass biotope; however, the distance between these species was closer than that of the hardground biotope species. The Bayesian mixing models run for E. lucunter at all four localities found differences in food resources contribution. The algae D. menstrualis, C. crassa and B. triquetrum dominated in CGD; whereas C. nitens, Gracilaria spp., and D. caribaea represented the main contributor algae to the diet of E. lucunter at LQY. In Culebra Island, no dominance of any particular algae was detected in TMD, where six of the eight species exhibited a similar contribution. Similarities in δ15N between D. antillarum and T. ventricosus may hint towards a similar trophic level for these species, although T. ventricosus is widely accepted as an omnivore, while D. antillarum is considered a generalist herbivore. The lack of overlap among species in the two biotopes seems to indicate a resource partitioning strategy to avoid niche competition among co-occurring species. Rev. Biol. Trop. 64 (2): 837-848. Epub 2016 June 01.

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Sea urchins are noted for the absence of neoplastic disease and represent a novel model to investigate cellular and systemic cancer protection mechanisms. Following intracoelomic injection of the DNA alkylating agent methyl methanesulfonate, DNA damage was detected in sea urchin cells and tissues (coelomocytes, muscle, oesophagus, ampullae and gonad) by the alkaline unwinding, fast micromethod. Gene expression analyses of the coelomocytes indicated upregulation of innate immune markers, including genes involved in NF-κB signalling. Results suggest that activation of the innate immune system following DNA damage may contribute to the naturally occurring resistance to neoplastic disease observed in sea urchins.

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The impact of the chemical changes in the ocean waters due to the increasing atmospheric CO2 depends on the ability of an organism to control extracellular pH. Among sea urchins, this seems specific to the Euechinoidea, sea urchins except Cidaroidea. However, Cidaroidea survived two ocean acidification periods: the Permian-Trias and the Cretaceous-Tertiary crises. We investigated the response of these two sea urchin groups to reduced seawater pH with the tropical cidaroid Eucidaris tribuloides, the sympatric euechinoid Tripneustes ventricosus and the temperate euechinoid Paracentrotus lividus. Both euechinoid showed a compensation of the coelomic fluid pH due to increased buffer capacity. This was linked to an increased concentration of DIC in the coelomic fluid and thus of bicarbonate ions (most probably originating from the surrounding seawater as isotopic signature of the carbon - δ¹³C - was similar). On the other hand, the cidaroid showed no changes within the coelomic fluid. Moreover, the δ¹³C of the coelomic fluid did not match that of the seawater and was not significantly different between the urchins from the different treatments. Feeding rate was not affected in any species. While euechinoids are able to regulate their extracellular acid-base balance, many questions are still unanswered on the costs of this capacity. On the contrary, cidaroids do not seem affected by a reduced seawater pH. Further investigations need to be undertaken to cover more species and physiological and metabolic parameters in order to determine if energy trade-offs occur and how this mechanism of compensation is distributed among sea urchins.

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Ocean temperatures are rising throughout the world, making it necessary to evaluate the impact of these temperature changes on sea urchins, which are well-known bioindicators. This study evaluated the effect of an increase in temperature on the immune response of the subtidal Lytechinus variegatus and the intertidal Echinometra lucunter sea urchins. Both species were exposed to 20 (control), 25 and 30 °C temperatures for 24 h, 2, 7 and 14 days. Counting of coelomocytes and assays on the phagocytic response, adhesion and spreading of coelomocytes were performed. Red and colorless sphere cells were considered biomarkers for heat stress. Moreover, a significant decrease in the phagocytic indices and a decrease in both cell adhesion and cell spreading were observed at 25 and 30 °C for L. variegatus. For E. lucunter, the only alteration observed was for the cell proportions. This report shows how different species of sea urchins respond immunologically to rising temperatures.

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Contact between humans and coastal areas has increased in recent decades, which has led to an increase in injuries from aquatic animals. The majority of these present dermatological manifestations, and some of them show typical lesions. The highest percentages of injuries that occur in marine environments are associated with invertebrates such as sea urchins, jellyfish and Portuguese men-of-war (echinoderms and cnidarians). In this review, we discuss the clinical, therapeutic and preventive aspects of injuries caused by marine and freshwater invertebrates, focusing on first aid measures and diagnosis for dermatologists and professionals in coastal areas.

O contato entre a Humanidade e as áreas litorâneas vem aumentando nas últimas décadas e com isso também aumentaram os acidentes por animais aquáticos. A maioria destes apresenta manifestações dermatológicas, sendo algumas bem características. As maiores porcentagens das lesões em ambientes marinhos estão associadas aos invertebrados, como os ouriços-do-mar, águas-vivas e caravelas (equinodermos e cnidários). Nesta revisão, são discutidos os aspectos clínicos, terapêuticos e preventivos de acidentes por invertebrados marinhos e fluviais e ressaltados os primeiros cuidados e os auxílios diagnósticos para os dermatologistas e profissionais das áreas litorâneas.

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The genus Diadema presently consists of seven species, two of which are known from the Brazilian coast: D. antillarum and D. ascensionis. The first is usually known for shallow coastal areas, while the second was apparently restricted to oceanic islands. In February 2011, a dense population of D. ascensionis was observed on the coastal reefs of Praia do Francês (Alagoas State, northeastern Brazil). Five specimens were collected and transported to the laboratory where morphological studies of the test and pedicellariae were conducted. Subsequently, visits were made to scientific collections in order to compare and confirm species identifications. Our observations confirm the presence of tridentate pedicellariae with narrow and strongly curved valves. The axial cavity in the tips of the spines is filled with dense nonreticular tissue. This taxonomic data confirms the occurrence of D. ascensionis in coastal areas. On the coastal reefs of Praia do Francês, animals were observed from the beach to the reef formations about 200 m offshore in areas with a sandy substrate and in reef cavities, usually in clear and well illuminated waters. Solitary individuals or groups of up to 15 individuals formed dense populations in the area. We stress the importance of pedicellariae for the specific identification of the Diadematidae, considering that they are quite constant and reliable at this taxonomic level. Our results demonstrate that D. ascensionis is not restricted to insular environments and that this species may be common in shallow coastal habitats.

O gênero Diadema é composto por sete espécies, das quais duas são conhecidas para o litoral brasileiro: D. antillarum e D. ascensionis. A primeira é principalmente conhecida em áreas costeiras, enquanto que a segunda está aparentemente restrita a ilhas oceânicas. Em fevereiro de 2011, uma densa população de D. ascensionis foi observada nos recifes costeiros da Praia do Francês, no Estado de Alagoas, Região Nordeste do Brasil. Cinco espécimes foram coletados e transportados ao laboratório, onde estudos morfológicos da carapaça e das pedicelárias foram desenvolvidos. Subsequentemente, foram realizadas visitas a coleções científicas para a comparação e a confirmação da espécie. As observações, neste trabalho, evidenciaram a presença de uma pedicelária tridentada com valvas estreitas e fortemente curvadas. A cavidade axial nas pontas dos espinhos é preenchida por um denso tecido não reticular. Estes dados taxonômicos confirmam a ocorrência de D. ascensionis em áreas costeiras. Nos recifes costeiros da Praia do Francês, os animais foram observados a partir da praia em direção às formações recifais localizadas a 200 m da praia, em áreas de substrato arenoso, e nas cavidades do recife, geralmente em águas claras e bem iluminadas. Os indivíduos estavam solitários ou formando grupos de até 15 indivíduos. Destaca-se a importância das pedicelárias na sistemática dos Diadematidae, tendo em vista que as mesmas são bastante constantes e confiáveis para a identificação em nível específico. Os resultados do presente trabalho demonstram que D. ascensionis não está restrita a ambientes insulares e que esta espécie pode ser comum em habitats costeiros rasos.

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RESUMO

The genus Diadema presently consists of seven species, two of which are known from the Brazilian coast: D. antillarum and D. ascensionis. The first is usually known for shallow coastal areas, while the second was apparently restricted to oceanic islands. In February 2011, a dense population of D. ascensionis was observed on the coastal reefs of Praia do Francês (Alagoas State, northeastern Brazil). Five specimens were collected and transported to the laboratory where morphological studies of the test and pedicellariae were conducted. Subsequently, visits were made to scientific collections in order to compare and confirm species identifications. Our observations confirm the presence of tridentate pedicellariae with narrow and strongly curved valves. The axial cavity in the tips of the spines is filled with dense nonreticular tissue. This taxonomic data confirms the occurrence of D. ascensionis in coastal areas. On the coastal reefs of Praia do Francês, animals were observed from the beach to the reef formations about 200 m offshore in areas with a sandy substrate and in reef cavities, usually in clear and well illuminated waters. Solitary individuals or groups of up to 15 individuals formed dense populations in the area. We stress the importance of pedicellariae for the specific identification of the Diadematidae, considering that they are quite constant and reliable at this taxonomic level. Our results demonstrate that D. ascensionis is not restricted to insular environments and that this species may be common in shallow coastal habitats.

O gênero Diadema é composto por sete espécies, das quais duas são conhecidas para o litoral brasileiro: D. antillarum e D. ascensionis. A primeira é principalmente conhecida em áreas costeiras, enquanto que a segunda está aparentemente restrita a ilhas oceânicas. Em fevereiro de 2011, uma densa população de D. ascensionis foi observada nos recifes costeiros da Praia do Francês, no Estado de Alagoas, Região Nordeste do Brasil. Cinco espécimes foram coletados e transportados ao laboratório, onde estudos morfológicos da carapaça e das pedicelárias foram desenvolvidos. Subsequentemente, foram realizadas visitas a coleções científicas para a comparação e a confirmação da espécie. As observações, neste trabalho, evidenciaram a presença de uma pedicelária tridentada com valvas estreitas e fortemente curvadas. A cavidade axial nas pontas dos espinhos é preenchida por um denso tecido não reticular. Estes dados taxonômicos confirmam a ocorrência de D. ascensionis em áreas costeiras. Nos recifes costeiros da Praia do Francês, os animais foram observados a partir da praia em direção às formações recifais localizadas a 200 m da praia, em áreas de substrato arenoso, e nas cavidades do recife, geralmente em águas claras e bem iluminadas. Os indivíduos estavam solitários ou formando grupos de até 15 indivíduos. Destaca-se a importância das pedicelárias na sistemática dos Diadematidae, tendo em vista que as mesmas são bastante constantes e confiáveis para a identificação em nível específico. Os resultados do presente trabalho demonstram que D. ascensionis não está restrita a ambientes insulares e que esta espécie pode ser comum em habitats costeiros rasos.

Assuntos

RESUMO

The genus Diadema presently consists of seven species, two of which are known from the Brazilian coast: D. antillarum and D. ascensionis. The first is usually known for shallow coastal areas, while the second was apparently restricted to oceanic islands. In February 2011, a dense population of D. ascensionis was observed on the coastal reefs of Praia do Francês (Alagoas State, northeastern Brazil). Five specimens were collected and transported to the laboratory where morphological studies of the test and pedicellariae were conducted. Subsequently, visits were made to scientific collections in order to compare and confirm species identifications. Our observations confirm the presence of tridentate pedicellariae with narrow and strongly curved valves. The axial cavity in the tips of the spines is filled with dense nonreticular tissue. This taxonomic data confirms the occurrence of D. ascensionis in coastal areas. On the coastal reefs of Praia do Francês, animals were observed from the beach to the reef formations about 200 m offshore in areas with a sandy substrate and in reef cavities, usually in clear and well illuminated waters. Solitary individuals or groups of up to 15 individuals formed dense populations in the area. We stress the importance of pedicellariae for the specific identification of the Diadematidae, considering that they are quite constant and reliable at this taxonomic level. Our results demonstrate that D. ascensionis is not restricted to insular environments and that this species may be common in shallow coastal habitats.(AU)

O gênero Diadema é composto por sete espécies, das quais duas são conhecidas para o litoral brasileiro: D. antillarum e D. ascensionis. A primeira é principalmente conhecida em áreas costeiras, enquanto que a segunda está aparentemente restrita a ilhas oceânicas. Em fevereiro de 2011, uma densa população de D. ascensionis foi observada nos recifes costeiros da Praia do Francês, no Estado de Alagoas, Região Nordeste do Brasil. Cinco espécimes foram coletados e transportados ao laboratório, onde estudos morfológicos da carapaça e das pedicelárias foram desenvolvidos. Subsequentemente, foram realizadas visitas a coleções científicas para a comparação e a confirmação da espécie. As observações, neste trabalho, evidenciaram a presença de uma pedicelária tridentada com valvas estreitas e fortemente curvadas. A cavidade axial nas pontas dos espinhos é preenchida por um denso tecido não reticular. Estes dados taxonômicos confirmam a ocorrência de D. ascensionis em áreas costeiras. Nos recifes costeiros da Praia do Francês, os animais foram observados a partir da praia em direção às formações recifais localizadas a 200 m da praia, em áreas de substrato arenoso, e nas cavidades do recife, geralmente em águas claras e bem iluminadas. Os indivíduos estavam solitários ou formando grupos de até 15 indivíduos. Destaca-se a importância das pedicelárias na sistemática dos Diadematidae, tendo em vista que as mesmas são bastante constantes e confiáveis para a identificação em nível específico. Os resultados do presente trabalho demonstram que D. ascensionis não está restrita a ambientes insulares e que esta espécie pode ser comum em habitats costeiros rasos.(AU)

Assuntos

RESUMO

The pantropical sea urchin genus Eucidaris contains four currently recognized species, all of them allopatric: E. metularia in the Indo-West Pacific, E. thouarsi in the eastern Pacific, E. tribuloides in both the western and eastern Atlantic, and E. clavata at the central Atlantic islands of Ascension and St. Helena. We sequenced a 640-bp region of the cytochrome oxidase I (COI) gene of mitochondrial DNA to determine whether this division of the genus into species was confirmed by molecular markers, to ascertain their phylogenetic relations, and to reconstruct the history of possible dispersal and vicariance events that led to present-day patterns of species distribution. We found that E. metularia split first from the rest of the extant species of the genus. If COI divergence is calibrated by the emergence of the Isthmus of Panama, the estimated date of the separation of the Indo-West Pacific species is 4.7-6.4 million years ago. This date suggests that the last available route of genetic contact between the Indo-Pacific and the rest of the tropics was from west to east through the Eastern Pacific Barrier, rather than through the Tethyan Sea or around the southern tip of Africa. The second cladogenic event was the separation of eastern Pacific and Atlantic populations by the Isthmus of Panama. Eucidaris at the outer eastern Pacific islands (Galapagos, Isla del Coco, Clipperton Atoll) belong to a separate clade, so distinct from mainland E. thouarsi as to suggest that this is a different species, for which the name E. galapagensis is revived from the older taxonomic literature. Complete lack of shared alleles in three allozyme loci between island and mainland populations support their separate specific status. Eucidaris galapagensis and E. thouarsi are estimated from their COI divergence to have split at about the same time that E. thouarsi and E. tribuloides were being separated by the Isthmus of Panama. Even though currents could easily convey larvae between the eastern Pacific islands and the American mainland, the two species do not appear to have invaded each other's ranges. Conversely, the central Atlantic E. clavata at St. Helena and Ascension is genetically similar to E. tribuloides from the American and African coasts. Populations on these islands are either genetically connected to the coasts of the Atlantic or have been colonized by extant mitochondrial DNA lineages of Eucidaris within the last 200,000 years. Although it is hard to explain how larvae can cross the entire width of the Atlantic within their competent lifetimes, COI sequences of Eucidaris from the west coast of Africa are very similar to those of E. tribuloides from the Caribbean. FST statistics indicate that gene flow between E. metularia from the Indian Ocean and from the western and central Pacific is restricted. Low gene flow is also evident between populations of E. clavata from Ascension and St. Helena. Rates of intraspecific exchange of genes in E. thouarsi, E. galapagensis, and E. tribuloides, on the other hand, are high. The phylogeny of Eucidaris confirms Ernst Mayr's conclusions that major barriers to the dispersal of tropical echinoids have been the wide stretch of deep water between central and eastern Pacific, the cold water off the southwest coast of Africa, and the Isthmus of Panama. It also suggests that a colonization event in the eastern Pacific has led to speciation between mainland and island populations.

RESUMO

A serious omission in ecological methodology is the absence of a rigorous statistical procedure to analyse multiple-choice feeding-preference experiments. A sample of 21 studies in the littoral marine context shows that results from such experiments are used to study a variety of conceptual issues, ranging from nutritional biology to ecosystem dynamics. A majority of such studies have been incorrectly analysed. The analytical problem has two facets: (1) lack of independence in the simultaneous offer of food types and (2) the existence of autogenic changes particular to each food type. Problem (2) requires the use of control arenas without the consumer. A recent advance allows the rigorous analysis of experiments with two food types offered simultaneously. Here I propose a method for the multiple-choice case. For the first problem I suggest the use of multivariate statistical analysis, providing both a parametric and a nonparametric procedure. The second problem is solved using basic statistical theory. I analyse data from an experiment with the sea urchin Tetrapygus niger feeding on three species of algae: Ulva nematoidea, Gymnogongrus furcellatus, and Macrocystis pyrifera. The parametric and nonparametric procedures yielded similar results, and showed that when offered the three species of algae T. niger does not feed at random but shows a preference for U. nematoidea. The method requires that the number of replicates in the treatment and control arenas be the same, and greater than the number of food types. The method is useful for other kinds of multiple-choice experiments.